Bolarus (Bolarus IX, Myrmidon): Blue, bald people. Membership: First courting membership in the 2260s, joined sometime in the 2270s-80s.

Bre’el IV: Overly stiff and formal people. Membership unknown.

Bynaus: Small pink computer people. Membership: 24th Century.

Cairn: Telepaths that speak in images. Membership: 2370.

Cait (Cait, Kirisha IV): Cat people. Membership: at least the 2250s, though they apparently leave and come back on a whim (presumably people call up the Caitian Councillor and ask him/her “will you be attending today, or have you left again? You’ve left? Okay, see you the session after next”).

That brings us to 105 or 106 (out of around 155 places to fill). Plus, the many other established or implied colony worlds may in some cases have Council membership, since Deneva, Izar and Cestus (even Alpha Proxima II) made it to the Council.